Implantable medical devices are often used to treat a variety of medical conditions. Examples of implantable medical devices include drug delivery devices, pain management devices, and devices that treat heart arrhythmias. One example of an implantable medical device used to treat heart arrhythmias is a cardiac pacemaker, which is commonly implanted in a patient to treat bradycardia (i.e., abnormally slow heart rate). A pacemaker includes a pulse generator and leads, which form the electrical connection between the pulse generator and the heart. An implantable cardioverter defibrillator (“ICD”) is used to treat tachycardia (i.e., abnormally rapid heart rate). An ICD also includes a pulse generator and leads that deliver electrical energy to the heart. Pulse generators typically include a housing for a battery and electrical circuitry and a header for connecting the leads to the pulse generator.
Implantable medical devices are also useful in the treatment of heart failure. For example, cardiac resynchronization therapy (“CRT”) (also commonly referred to as biventricular pacing) is an emerging treatment for heart failure, which involves stimulation of both the right and the left ventricles to increase hemodynamic efficiency and cardiac output. The treatment of heart failure and heart arrhythmias can be enhanced through the use of chronically implanted sensors. For example, it can be useful to place a pressure sensor in the vasculature because the diastolic pressure can be a good predictor of decompensation in heart failure patients. Pressure sensors can also be used as part of pacing or defibrillation therapy. Communication between the implantable medical device and the chronically implanted sensor can allow the sensor data to be downloaded by a clinician or used to modify the therapy delivered by the implantable medical device. There is therefore a need for an implantable medical device that includes a transducer for communication with a chronically implanted sensor.